How Auroras Work

Destination - Iceland  Comment
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The science behind the breathtakingly beautiful phenomenon of  the nocturnal light shows called auroras is fascinating.
The layers of the sun’s atmosphere (photosphere, chromosphere, corona) become increasingly cooler, moving away from its core at15 million degrees Celsius to its surface at 6,000 degrees Celsius. Sunspots, visibly dark areas within the sun, or areas of significantly lower temperature, 4000 degrees Celsius, occur continuously, ebbing and peaking in frequency in 11 year cycles. High sunspot counts correlate with high levels of solar activity. Unlike the bright loops of energy that can be seen on the sun’s surface as particles flow along lines within the sun’s magnetosphere, the darker areas or coronal holes exist where magnetic lines have only one anchor point in the sun’s magnetosphere, allowing plasma to escape.
This plasma carries part of the sun’s magnetic field with it; the interplanetary magnetic field or IMF. The density of the solar wind decreases with distance but its sphere of influence, the heliosphere, reaches past our solar system’s outer planets. The sun’s rotation causes this field to radiate in a spiral structure.
The speed of the solar wind averages 450 km/s but often varies significantly from 300 km/s to 1000 km/s. Large variances in the solar wind’s velocity, density, and magnetic can cause significant terrestrial disturbances.
The solar wind constantly distorts the earth’s magnetic field (caused by the rotating metallic fluids of its core) compressing it on the light side, into a half sphere, and elongating it on the dark side, in a tube, similar to the shape of a comet’s tail. As the supersonic solar wind approaches the obstacle of the earth’s magnetic field a shock front is formed; as the solar wind is directed around the earth, smaller magnetic waves occur between the earth and the sun slowing and changing the course of the streaming plasma.
Surrounding the axis of the magnetic field, offset 11 degrees from the geophysical axis, are weaker areas that give energy rich solar particles little resistance. The charged solar particles that do make it into the upper atmosphere (ionosphere) excite electrons causing them to jump to higher orbits temporarily before they return to their original orbits by giving off auroral radiation and producing visible light in the process.


Auroras (borealis in the north and australis in the south) are produced by the solar wind, fast-moving charged particles that escape the sun’s gravity, exciting gases in the earth’s upper atmosphere.
The color of auroral emissions is determined by the gases excited, primarily oxygen and nitrogen. Altitude also influences color; red is found above 200 km, yellow and green between 180 – 110 km, and blue and violet below that. These altitudes vary between dayside and nightside aurora; at night blue and green altitudes drop increasing in intensity, while red rises decreasing intensity.
Auroras appear most consistently, almost continuously, and intensely in an oval band that rings the magnetic poles; in the north 67 degrees magnetic latitude at magnetic noon and 76 degrees magnetic latitude at magnetic midnight. Additionally a thinner weaker band of increased occurrence bisects this oval along a straight line between the sun and the earth.
Auroras occur by night and by day. The difference between night and day auroras is the number of particles (greater in the day), the amount of energy the particles carry (less by day), and the dominant color (green by night, red by day). Dayside aurora only occur inside the auroral oval at high polar latitudes and are only visible when it is dark during the day.
Auroras are extremely dynamic. Their zone of maximum occurrence can change by several hundred kilometers in minutes. And they can vary in orders of magnitude within seconds.
It’s small wonder that these fantastic colored lights that dance in mesmerizing patterns filling the heavens above have held a never-ending fascination for those who are lucky enough to witness them, whether first or second hand. They’re divine.
Learn more about night photography in my digital photography workshops.
Find out about my Iceland Auroras workshop here.

13 Essential Tips For Low Light & Night Photography

Technique - Exposure  Comment
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What settings should you use when making exposures in low light or at night? Use a tripod and cable release, set ISO to 800 (or higher), open up f5.6 or wider, focus at infinity and keep exposures below 20 seconds. While this is a good starting point, that’s all it is, as you’ll need to modify settings based on the specific light(s) in a location, the equipment you’re using, and the effect you want to produce. Instead, ask, “What concerns do I need to be mindful of and what points of control do I have when making low light or night photographs?” Develop your sensitivity to these factors and you’ll know why and when to improvise and even what more you can explore. These twelve tips will give you a solid foundation from which to begin your explorations in low light and night photography.


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New Movie & Book – Chasing Ice – James Balog

Books, Video  Comment
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Premiered at the Sundance Film Festival in January and opening in New York and Toronto Nov 9, Chasing Ice is a documentary feature, directed by Jeff Orlowski, that reveals the work of photographer James Balog and his Extreme Ice Survey (EIS) project. Balog, once a skeptic about climate change, discovers through EIS undeniable evidence of a warming world. Chasing Ice features hauntingly beautiful, multi-year time-lapse videos of vanishing glaciers, while delivering fragile hope to our carbon-powered planet.
Find out more about the film here.

A companion book is also now available. ICE: Portraits of the World’s Vanishing Glaciers (288 pages),celebrating the stupendous forms, colors and textures in arctic and alpine landscapes, will be released in the fall of 2012 in collaboration with Rizzoli, the world-renowned publisher of art books. Terry Tempest Williams, one of America’s most distinguished environmental writers and thinkers, will contribute the foreword.
Preview the book ICE here.
Find out more about photographer James Balog here.

PHOTOGRAPH – The New eMagazine

Magazine, Magazine - PHOTOGRAPH  Comment
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There’s a new electronic magazine in town – and I’m delighted to be a part of it.
The 132 pages in Issue One of PHOTOGRAPH, A Digitial Quarterly Magazine for Creative Photographers. features …
Columns include Martin Bailey’s The Art of the Print, John Paul Caponigro’s Creative Composition, Kevin Clark’s The Studio Sketchbook, David Duchemin’s Without The Camera, Chris Orwig’s Creativity, and Piet van Den Eynde’s Lightroom Before + After.
Portfolios by Art Wolfe, Nate Parker, and Bruce Percy are followed by short interviews.
Featured articles by Younes Bounhar, Andrew Gibson, Jay Goodrich, Al Smith, and Nicole Young.
PHOTOGRAPH is available now through Craft & Vision, as a PDF download, for USD$8. A 4-issue subscription for US$24 (or buy 3 issues and get one free). You can subscribe today, or, if you want to do so risk-free, we’ll send a short email to everyone that buys Issue One and give you the chance to top-up your subscription with the remaining 3 issues for US$16, as long as you do it before the end of November 2012.
Find out more and subscribe on David Duchemin’s blog.

Here’s an excerpt from the first article in my column Creative Composition.
Dynamics Not Rules
“When it comes to composition, there are no rules . . . except, perhaps, never say never and always avoid saying always. I recommend you don’t ask, “Should I . . .?”; rather, ask “What happens when I . . . ?”. But there are principles. Each element has a unique force and contributes to the whole. Each element influences the other, creating a cascading chain of action, reaction, and interaction. These forces are definable and consistent, so you can understand them and apply them repeatedly. An understanding of what these elements are will open up possibilities and create opportunities for you. An understanding of how each element works will help you apply it so that you can improvise given the unique characteristics of a specific situation and your own con- cerns. Versatility with many strategies enables you to be more successful in more varied situations and to make more varied statements. Understanding the principles of visual dynamics will help make your decision making pro- cess more informed, but it won’t make choices for you. Awareness is the key. Better awareness brings better choices. Better choices bring better results …”

Weaving Narratives In Museum Galleries – Thomas P Campbell

Video, Video - TED  Comment
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“As the director of the Metropolitan Museum of Art in New York, Thomas P. Campbell thinks deeply about curating—not just selecting art objects, but placing them in a setting where the public can learn their stories. With glorious images, he shows how his curation philosophy works for displaying medieval tapestries—and for the over-the-top fashion/art of Alexander McQueen.”

Green Action – Limit Your Use of Antibacterial Soaps

Environment - Green Actions  Comment
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Be more green!
You can make a difference today!
Make many small changes to make one big change!
And you’ll save a lot!
Take action now!
Here’s one idea.
Try Limiting Your Use of Antibacterial Soaps    
 We are heading in the holiday season which comes “hand in hand” with the cold and flu season.  We have all been told to sneeze into our sleeves and wash our hands often to keep the germs at bay.  There is a whole industry built on keeping people safe and germ free. Consumers in the United States spend almost $1 billion per year on “antibacterial” soaps and other products, often believing these products will protect their families from harmful germs and illnesses. So one would think, with all these special wipes and soaps we should be protected.  Recently, new research has some scientists concerned that we might be harming ourselves as well as endangering our environment by using these antibacterial soaps.
Let’s look at the facts.  Most of us use these products to prevent cold and flu viruses.  When actually these antibacterial products kill bacteria, not viruses. These soaps are made up of two major antimicrobial’s, Triclosan, and Triclocarban.  These antibiotics soaps and wipes were originally created in the 1960’s for use before surgical procedures.  They were commercialized in the 1980’s, and by 2001 over 76 percent of liquid hand soaps contained these chemicals.  Most scientific research has proven that the over-use of these chemicals can reduce the overall effectiveness of antibiotics.  The more we use these chemicals the more resistant they become to bacteria, the more difficult it becomes for us to fight off disease.
When we wash our hand these chemicals are absorbed into our skin and contaminate our blood and urine.  One study found that 97 percent of all US women showed levels of triclosan in their breast milk.   According to data from the Centers for Disease Control and Prevention (CDC), levels of triclosan in humans have increased by an average of 50 percent since 2004. Initial studies found that human blood levels of triclocarban spiked after using soaps containing the chemical.
The effect of these chemicals does not end after we wash our hands. Most of these product are washed down the drain thru urine or waste water during washing.   Triclosan is one of the most frequently detected chemicals in streams across the U.S. It has even been found in the bodies of wild bottlenose dolphins. Both triclosan and triclocarbon are found at high concentrations in treated sewage sludge (also known as biosolids) that is often applied to agricultural fields as fertilizer. Because triclosan has been shown to accumulate in earthworms living in these fields, there are concerns about these chemicals also moving into plants and wildlife. In 2002, the USGS published a landmark study showed 80 percent of 139 streams sampled from across 30 U.S. states were found to contain measurable levels of organic wastewater contaminants. Triclosan has also been found to inhibit photo-synthesis in diatom algae.  These algae are responsible for a large part of the photosynthesis on Earth.
While we know very little about the other long term effects of these chemicals that we are using, what we do know is that these chemicals may not help us or our environment stay healthier.
There are alternatives, many are organic and far less harmful to us and our environment.
What can we do to limit our use of these chemicals?
1) Wash your hands carefully and more frequently with natural soaps.
2) Use organic products that contain olive oil, honey, and candula oil.
3) Stay away from products that contain harsh ingredients ie: chlorine, ammonia or glycol ether.
In general, be careful of not only what you put on/in your body but also of what you wash down the drain or put in landfills.
Find more resources that will help you take action now here.
Find environmental organizations to support here.